1. Field of the Invention
The present invention relates to a method for assessing a ripple of a signal, which may be used in particular during operation of an internal combustion engine.
2. Description of the Related Art
For reasons of operational safety and product reliability and due to legal requirements, electronic and/or electromechanical components of more complex structures include one or more diagnostic systems. With the aid of such systems, it is possible to establish errors, ascertain the type and origin of established errors, and prompt the particular component or a higher-order unit to reduce or eliminate effects of the errors on the component or on an entire system. A suitable emergency function may be activated for this purpose, for example. If an error occurs, it may also be stored as an error entry in an error memory, in order to be able to take targeted measures in a service workshop.
In onboard systems of motor vehicles, corresponding onboard diagnostic systems (OBD) monitor a majority of the electronic and/or electromechanical components. Depending on the type of the particular studied error, a diagnosis may be carried out by the onboard diagnostic system continuously or only under certain conditions. For example, a check for electrical errors, e.g., short circuits or load drops, is typically performed continuously.
Under certain circumstances, so-called false-positive errors may also occur in this case. Thus, it is known that voltage ripples in a supply signal which powers a corresponding diagnostic device or the device to be diagnosed, for example, a voltage signal of a generator or a motor vehicle battery, may impair a corresponding error recognition function. Incorrect entries in an error memory thus occur, for example, which do not originate from an actual error.
Therefore, there is a demand for a more reliable execution of error diagnostic functions, in particular in onboard diagnostic systems. In particular, there is a demand for a capability of recognizing an outsized ripple in a signal.